In the video, Flint Farmer was lying on the grass between the curb and the sidewalk. It was shortly before 2 a.m. on a June morning in the West Englewood neighborhood, and Farmer had been shot by a Chicago police officer. Then, according to the video, the veteran officer, Gildardo Sierra, stepped onto the parkway and walked a semicircle about the prone Farmer as three bright flashes went off.

That shooting was the third by the officer since January — and the second fatality in those six months, records show.

Sierra fired 16 shots at Farmer, hitting him seven times, autopsy reports show. A Cook County deputy medical examiner, after performing an autopsy and later reviewing the video, said the three shots in the back were the fatal wounds.

Sierra told investigators he feared for his life because he believed Farmer had a gun.

In fact, Farmer was only holding a cellphone.

Despite the video, the Police Department ruled Farmer's June 7 death justified, just as it had Sierra's other two shootings this year. But police Superintendent Garry McCarthy said he considers the Farmer case "a big problem" and told the Tribune that the officer involved should not have been on the street given his history of shootings.

The shooting is under investigation by the FBI, the Tribune has learned.

Together, the three shootings raise questions about the department's efforts to detect and track officers involved in multiple shootings, even over a short period of time. The shootings also renew long-standing concerns about the department's ability to investigate itself and reinforce the need for independent inquiries.

Indeed, the shootings are under investigation by the Independent Police Review Authority, the city agency that independently investigates shootings by police

A 2007 Tribune investigation of a decade's worth of shootings by Chicago police found that the department often cleared officers of wrongdoing after only cursory investigations, even when the officers shot people in the back or from behind. The newspaper's investigation found that officials repeatedly failed to interview key witnesses and consider important forensic evidence in a rush to exonerate officers.

McCarthy told the Tribune the previous administration failed to recognize a pattern in police shootings and had no mechanism to track if officers were repeatedly involved in shootings. He also said the department did not have a system in place to monitor the emotional and psychological state of officers involved in shootings, suggesting they could be suffering from post-traumatic stress disorder and should be kept off the streets until they are better.

Without naming Sierra, he said the first two shootings were justified but that the officer should have been assigned to desk duty before Farmer was shot.

"He shouldn't have been where he was," McCarthy said during a recent meeting with the Tribune editorial board. "We should've had him off the street so that he was not in that particular environment and that problematic type of scenario."

McCarthy confirmed that Sierra is the only officer who has been stripped of his police powers for an on-duty shooting incident since he became superintendent in May.

Sierra, 31, joined the department nine years ago and received his police union's distinguished service award in 2005.

"The video does not catch everything," Sierra told the Tribune. "It's only part of the incident."

He declined to comment further, saying he had been instructed not to speak to the media by the Police Department and his union.

All three of Sierra's shootings took place after midnight in the crime-ridden Englewood and West Englewood neighborhoods, an impoverished area where three officers have been killed in the last decade. There were 43 murders, 78 sexual assaults and 753 robberies in that police district from January through September — the worst of any district in the city in all three categories, according to department statistics.

The first shooting involving Sierra occurred around 1:30 a.m. Jan. 7 when he and his partner stopped a green Oldsmobile Aurora similar to one implicated in earlier gunfire. The driver, Darius L. Pinex, handed over his license and registration but refused a request to turn off his engine and get out of the car, according to police reports.

Pinex's passenger then opened his door and Pinex made a furtive movement with his hand, the report said. The move prompted one of the officers to reach for his gun and order Pinex to show his hands, the reports said.

Pinex then threw the car into reverse and began dragging one of the officers, according to the police reports. Believing his partner and the passenger were in jeopardy, the other officer fired at the car, police said. The officers both told investigators that Pinex hit a light pole while in reverse, shifted the car into drive and gunned the vehicle forward. Both officers then opened fire, records show.

Pinex, a 27-year-old alleged gang member with a history of drug arrests, was shot three times, including once in the head, according to an autopsy report. When detectives arrived at the scene, they found a handgun underneath the driver's seat, police reports show. Pinex's right foot was resting on the brake, according to the reports.

His family filed a federal lawsuit Friday against Sierra and the city of Chicago. Farmer's family also has sued.

"I don't know if that policeman is angry or afraid of working in this neighborhood, but he's trigger-happy and he needs to be off the street," said his mother, Gloria Pinex. "We need to make sure he pays, so he doesn't do this to anyone else's mother."

Less than three months after Pinex's death, Sierra and his partner responded to a shots-fired call at 12:30 a.m. March 22 near West 59th Street and South Princeton Avenue, an area plagued by gang and drug problems even by Englewood standards. Dion Richards, then 19, pointed a gun at the officers, forcing them to shoot, the department has said.

Richards was hit in the leg. He was taken to a hospital and later charged with aggravated assault of a police officer with a firearm and aggravated unlawful use of a weapon. Police said they found a gun at the scene.

As part of a deal with prosecutors, Richards pleaded guilty in July and was sentenced to a year in prison. Because he had already served 113 days in custody, he spent two more months in prison.

McCarthy said the department did not have a system to track the frequency of an individual officer's shootings, something he said might have led supervisors to take Sierra off the street at that point.After Farmer's death, the superintendent implemented a policy in which an officer's history, including previous shootings, and mental state are reviewed after a shooting, the department said.

"We failed as management in that particular case because there was no mechanism to review how many shootings someone was in and what their assignment is and how they were feeling," the superintendent said. "Get them to the doctor. Get them to sit down, relax, take it easy. Maybe that's an officer we want on a desk job."

Craig Futterman, a University of Chicago law professor who works on police accountability issues, said the department historically has not tracked patterns of behavior by officers.

"Do they have the capacity to track patterns? Yes. Do they proactively do it? I've seen no evidence of it," Futterman said.

Sierra continued to work the overnight shift in Englewood after the first two shootings, typically patrolling from 9 p.m. to 6 a.m. He was on patrol around 2 a.m. June 7 when he and a partner responded to a domestic-disturbance call allegedly involving Flint Farmer and his girlfriend in the 6200 block of South Honore Avenue.

Confronted by the officers about beating his girlfriend and her 3-year-old daughter, Farmer allegedly fled through an empty lot to South Wolcott Avenue, one street over.

Farmer, 29, an unemployed store clerk with a small child and a prior domestic-violence arrest, fell to the ground, according to police reports. The bullets that pierced his abdomen and thigh had been fired by Sierra, who was standing in the street, records show. Moments later, a squad car responded to the scene, officials say, and captured video of Sierra as he stepped onto the parkway, walked about the unarmed Farmer in a semicircle and fired three more shots.

Farmer was pronounced dead at the scene.

Dr. Mitra Kalelkar, who performed the autopsy on Farmer, said he could have survived the shots in the abdomen and thigh, but the shots in the back killed him. Those shots, which coursed downward, hit Farmer's heart and lung, according to Kalelkar's report.

"All three were definitely fatal wounds," she told the Tribune.

Kalelkar said she viewed the video of the shooting after the lawyer for Farmer's survivors brought it to her. She recalled seeing the bright muzzle flash that accompanied each shot. When she considered the video in context with her autopsy report, she said it was evident that Farmer was on the ground when shot, that he was shot in the back and that those were the fatal shots.

"If I put it together with the video, he was definitely shot while on the ground," she said.

Farmer's is one of 51 police-involved shootings through the first nine months of this year, already exceeding the 44 for all of 2010, according to the city.

Farmer's father, Emmett, said the tragic chain of events reminded him of the LaTanya Haggerty case, a 1999 incident in which a 26-year-old computer programmer was fatally shot by police after she rode in a car that led officers on a 31-block chase. She raised a tiny object at an officer when the car stopped, prompting the officer to open fire and kill her. The object was also a cell phone.

On learning of the shooting from a relative, Farmer initially assumed his son must have been armed for Sierra to have fired 16 rounds at him.

"The (police) report says 'justifiable homicide.' I don't really understand how that could be," Farmer said in a recent interview. "What was justifiable where you shoot someone down like a dog?"

"It's an outrage that this cop was on the streets of Englewood," he said. "… This never should have happened."

Police and court records connect Sierra to the three shootings by either name or star number. Sierra told the Tribune that his three shootings this year are under review by IPRA. He also acknowledged he shot a dog this year.

IPRA refers some of its investigations to the Cook County state's attorney's office and federal authorities. A spokeswoman for the state's attorney declined to comment.

Farmer's father said he had been interviewed by an FBI agent about his son's shooting. Sean Macmanus , a spokesman for the FBI in Chicago, confirmed a civil rights investigation is under way in the Englewood area but would not say whether it involved Sierra.

McCarthy told the Tribune that the officer could face criminal charges.

"One of the big questions I got when I got here was are you going to have our backs," McCarthy said. "I said, 'Absolutely … but I'm not going to defend indefensible behavior and don't expect me to.'"